[Pharmacological Chaperone Therapy for Fabry Disease].

Pharmacological chaperone therapy (PCT) structurally stabilizes mutant enzyme proteins and increases their activity. Although ease of oral administration and effectiveness in patients with central nervous system disorders serve as advantages, PCT is effective only for patients with amenable mutations because its efficacy depends on gene mutations. PCT, which prevents progression of Fabry cardiomyopathy and nephropathy, was approved in Japan in 2018. It is expected that PCT will also be developed for lysosomal diseases that cause central nervous system disorders in the future.

Experience with enteral sulfonylurea monotherapy for extremely low birth weight infants with hyperglycemia.

Limited data are available on the effects of enteral sulfonylurea (SU) monotherapy in extremely low birth weight infants (ELBWIs) with hyperglycemia. Therefore, we report our experience with enteral SU monotherapy for hyperglycemic ELBWIs. We retrospectively evaluated 11 hyperglycemic ELBWIs (seven male infants, median gestational age = 24.9 wk) who received SU between January 2016 and December 2019. Blood glucose (BG) levels were monitored before and after SU initiation and evaluated for the occurrence of adverse effects. We administered SU at a median of 15 d (interquartile range [IQR]: 12-20 d) after birth, with the median maximum dose of 0.2 mg/kg/d (IQR: 0.125-0.3 mg/kg/d). Hyperglycemia improved in all patients, and the target BG levels were achieved without severe side effects at a median of 6 d (IQR: 4-8.5 d) after initiation of treatment. The incidence of hypoglycemia during SU treatment was observed in 18 events per 1000 patient hours; however, the patients were asymptomatic. Based on these results, enteral SU monotherapy may be considered as an option for hyperglycemic ELBWIs.

The role of native T1 values on the evaluation of cardiac manifestation in Japanese Fabry disease patients.

Aims: T1 mapping in cardiac magnetic resonance imaging enables us to distinguish various myocardial diseases showing left ventricular hypertrophy. Fabry disease is a lysosomal storage disorder causing the accumulation of glycosphingolipids into various organs, including the heart, which can be detected by native T1 values in T1 mapping. However, there is no report for the systematic evaluation of native T1 values in Fabry disease in Japan. Methods and results: We analyzed native T1 values of 30 Fabry disease patients (14 males and 16 females) obtained by 3-T cardiac magnetic resonance imaging. Averaged T1 values were significantly lower in male patients (septal T1: 1149.5 ± 63.3 ms; total T1: 1145.1 ± 59.5 ms) than in female patients (septal T1: 1210.5 ± 45.5 ms; total T1: 1198.8 ± 51.8 ms) (p < 0.01). We compared the native T1 values of Fabry disease patients with those obtained from 15 hypertrophic cardiomyopathy patients (9 males and 6 females). Native T1 values effectively differentiate Fabry disease from hypertrophic cardiomyopathy (septal T1: sensitivity 93.3% and specificity 80.0%; total T1: sensitivity 86.7% and specificity 73.3%). In addition, native T1 values had a significant negative correlation with the left ventricular mass index in male patients at the pre-hypertrophic stage (p < 0.05). In male and female patients without late-gadolinium enhancement, native T1 values also had a significant negative correlation with the left ventricular mass index (p < 0.05). Conclusion: These results suggest that native T1 values can be used to discriminate Fabry disease from hypertrophic cardiomyopathy and can reflect the accumulation of glycosphingolipids in cardiomyocytes.

Clinical outcomes in pregnant women with coronavirus disease 2019 in a perinatal medical centre in Japan: a retrospective study of the first 1 year of the pandemic.

In this retrospective study, we analysed clinical and demographic data from the medical records of 31 pregnant women with coronavirus disease 2019 (COVID-19) who were treated at our hospital between April 2020 and April 2021. The most common symptom was a fever; ∼10% of patients were asymptomatic. One patient with rapidly worsening pneumonia needed a Caesarean Section at 30 weeks and was admitted for intensive care. Twelve patients received perinatal care in our hospital (10 live births, one stillbirth, and one artificial abortion). Six patients delivered vaginally; the others delivered via caesarean section. Two patients had complications, including severe hypertensive disorders and preeclampsia. All patients recovered from COVID-19. Severe acute respiratory syndrome coronavirus 2 was not detected in the placenta, umbilical cord, cord blood, amniotic fluid, vaginal fluid, or breast milk in any patient. There were no neonatal adverse outcomes. The possibility of transmitting the coronavirus to pregnancy-related samples was low.IMPACT STATEMENTWhat is already known on the subject? COVID-19 has been affecting different countries in diverse ways, and the incidence, mortality, and morbidity rates of patients with COVID-19 vary widely by country or region and race. These differences in results may reflect racial differences and differences in national health care systems. Moreover, the information about the perinatal outcomes of pregnant women with COVID-19 and their newborns from Japan is limited.What do the results of this study add to what is known? We described the perinatal outcomes of 31 Japanese pregnant women with COVID-19 who were managed safely in a perinatal medical centre in Tokyo Japan, during the first 1 year of the pandemic.What are the implications of these findings for clinical practice and/or further research? Severe pneumonia and perinatal complications may occur, although no maternal and neonatal deaths were observed for COVID-19-positive pregnant women in our facility. Therefore, it is important to prevent this infection during pregnancy with the provision of effective medical care.

Risk factors for hyperglycemia in extremely low birth weight infants during the first 14 days.

BACKGROUND: There are limited data regarding the risk factors for hyperglycemia in extremely low birth weight infants (ELBWIs). The aim of this observational study was to investigate the incidence of hyperglycemia among ELBWIs during the first 14 days of life and identify independent risk factors for hyperglycemia development. METHODS: We retrospectively evaluated 55 ELBWIs (32 male infants) between January 2015 and March 2020. Hyperglycemia was diagnosed when the glucose level was ≥180 mg/dL. Demographic and clinical data were extracted from the patients' medical records. The risk factors associated with the onset of hyperglycemia were identified by Cox proportional hazards regression analysis with variables that had previously been identified as risk factors for hyperglycemia. RESULTS: Hyperglycemia developed in 23 patients (41.8%) within the first 14 days of life. Gestational age, chorioamnionitis, postnatal intravenous glucocorticoids, and probiotic type were included in the analysis. The results indicated that hyperglycemia was significantly associated with gestational age (hazard ratio [HR], 0.65; 95% confidence interval [CI], 0.48-0.87; P = 0.004). Further, Bifidobacterium breve (B. breve M-16V) use was related to hyperglycemia in ELBWIs (HR, 2.95; 95% CI, 1.10-7.87; P = 0.031). CONCLUSION: Hyperglycemia was strongly associated with lower gestational age and B. breve M-16V use in our study population. Although probiotic supplementation may be beneficial for preterm infants to reduce the incidence of necrotizing enterocolitis, the dextrin used as an excipient in B. breve M-16V may lead to an undesirable carbohydrate load in ELBWIs.

Update of the genotype and phenotype of KMT2D and KDM6A by genetic screening of 100 patients with clinically suspected Kabuki syndrome.

Kabuki syndrome is characterized by a variable degree of intellectual disability, characteristic facial features, and complications in various organs. Many variants have been identified in two causative genes, that is, lysine methyltransferase 2D (KMT2D) and lysine demethylase 6A (KDM6A). In this study, we present the results of genetic screening of 100 patients with a suspected diagnosis of Kabuki syndrome in our center from July 2010 to June 2018. We identified 76 variants (43 novel) in KMT2D and 4 variants (3 novel) in KDM6A as pathogenic or likely pathogenic. Rare variants included a deep splicing variant (c.14000-8C>G) confirmed by RNA sequencing and an 18% mosaicism level for a KMT2D mutation. We also characterized a case with a blended phenotype consisting of Kabuki syndrome, osteogenesis imperfecta, and 16p13.11 microdeletion. We summarized the clinical phenotypes of 44 patients including a patient who developed cervical cancer of unknown origin at 16 years of age. This study presents important details of patients with Kabuki syndrome including rare clinical cases and expands our genetic understanding of this syndrome, which will help clinicians and researchers better manage and understand patients with Kabuki syndrome they may encounter.

Massive accumulation of globotriaosylceramide in various tissues from a Fabry patient with a high antibody titer against alpha-galactosidase A after 6 years of enzyme replacement therapy.

Fabry disease is an X-linked metabolic disorder due to a pathogenic mutation of the GLA gene. The accumulation of globotriaosylceramide (Gb3) damages multiple organs, including the heart, kidney and nervous system, especially in classical type Fabry disease. Enzyme replacement therapy (ERT) using recombinant alpha-galactosidase A has been shown to remove Gb3 from organs and to improve the prognosis of Fabry disease. We herein report the case of a 67-year-old classical type Fabry patient who had been treated with ERT for 6 years and who continuously showed a high antibody titer against recombinant alpha-galactosidase A during therapy. A post-mortem examination was performed after sudden death. A histological examination revealed the massive accumulation of Gb3 in various organs, even after long term ERT. In addition to the typical pathological findings as reported in tissue biopsy samples, the serious accumulation of Gb3 in the cardiac conduction system and the endocrine system was detected. Since the start of ERT for this patient might be too late to improve organ damage and prognosis, ERT should be started before the appearance of major organ involvement for the effective elimination of Gb3 and changes in the therapeutic strategy might be considered if the patient shows a high antibody titer against recombinant alpha-galactosidase A.

Clinical findings of gadolinium-enhanced cardiac magnetic resonance in Fabry patients.

BACKGROUND: Fabry disease is one of the causes of left ventricular hypertrophy (LVH) and can be treated with enzyme replacement therapy or pharmacological chaperone therapy. Late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR) can identify myocardial fibrosis and be used for the stratification in LVH. However, the details of the prevalence and characteristics of LGE in Japanese Fabry patients have not been reported. METHODS: We evaluated myocardial involvement in 26 Fabry patients (10 males, 16 females) using gadolinium-enhanced CMR. LGE areas were analyzed using the previously reported scoring method. Echocardiography was also performed to evaluate the left ventricular function and left ventricular mass. RESULTS: LGE on CMR images was positive in 5 out of 26 patients, and all patients with LGE-positive findings suffered from LVH (2 out of 5 male patients and 3 out of 4 female patients with LVH on echocardiography). LGE was specifically localized at the mid-wall in the infero-lateral area of the left ventricle. LGE-positive patients seemed to be older, and tended to have a larger left ventricular mass index and higher B-type natriuretic peptide level than LGE-negative patients. CONCLUSIONS: These results revealed that specific localization of LGE was present in Fabry patients.

Characteristics of the Electrocardiogram in Japanese Fabry Patients Under Long-Term Enzyme Replacement Therapy.

Objective: An electrocardiogram (ECG) is an important tool for demonstrating cardiac manifestations in various heart diseases. The present study clarified the characteristics of ECG parameters in Japanese Fabry patients under long-term enzyme replacement therapy (ERT). Methods: We analyzed the ECGs of 40 Fabry patients (male, n = 17; female, n = 23) before and after treatment with ERT. To evaluate the atrio-ventricular conduction, the PQ interval, corrected PQ and PQ minus P-wave in lead II (Pend-Q) were calculated. The QRS duration, QTc, Sokolow-Lyon index, and strain pattern were also examined. Results: At the baseline, the shortening of the PQ interval, corrected PQ and Pend-Q was identified in 7.5, 25.0, and 47.5% of cases, respectively. The prolongation of QRS duration and QTc was found in 7.5 and 40.0% of cases, respectively. The strain pattern was mainly identified in female patients, irrespective of left ventricular hypertrophy (LVH). During long-term ERT, the PQ interval, corrected PQ and Pend-Q did not change significantly. The QRS duration was significantly prolonged in both genders, whereas the QTc was significantly prolonged only in male patients. A subgroup analysis revealed that the prolongation of the QRS duration and QTc only occurred in male patients with LVH and only occurred in female patients with the classical type mutation. The prevalence of the strain was significantly increased only in male patients with LVH. Conclusions: These results suggest that the shortening of the Pend-Q is a specific finding in Japanese Fabry patients, and the strain pattern without LVH in female patients can be considered Fabry disease. During long-term ERT, prolongation of the QRS duration and QTc can indicate the progression of myocardial damage in male patients with LVH and in female patients with the classical type mutation.

Mutation spectrum of α-Galactosidase gene in Japanese patients with Fabry disease.

The efficacy of pharmacological chaperone therapy for Fabry disease depends on the type of α-galactosidase A (GLA) mutations. Here, we examined the mutation spectrum of the GLA gene among patients from 115 Japanese families with Fabry disease. Of these, no pathogenic mutations were identified in six families (5.2%). In total, 73 different disease-causing mutations were identified: 41 missense (56.2%), 11 nonsense (15.1%), four in frame deletion (5.5%), 10 frameshift (13.7%), six splice site (8.2%), and one intronic (1.4%) mutations. The GLA mutations detected in later-onset phenotype patients with end-stage renal disease overlapped with those seen in classical patients, indicating that it is difficult to differentiate between these two phenotypes from gene mutations. Additionally, 33 families (28.7%) had amenable mutations to the pharmacological chaperone migalastat. In conclusion, our study is informative when considering genetic counseling and pharmacological chaperon therapy for Fabry disease.

Characterization of a Small Supernumerary Marker Chromosome Derived from Xq28 and 14q11.2 Detected Prenatally.

We present the characterization of a case with a small supernumerary marker chromosome (sSMC) detected prenatally derived from Xq28 and 14q11.2 maternal translocation. A 33-year-old Japanese woman, primigravida, underwent amniocentesis because of fetal growth restriction and fetal structural abnormality at 30 weeks of gestation. The fetal karyotype was identified as 47,XY,+mar. Additionally, the single nucleotide polymorphism array analysis revealed copy number gains at Xq28 and 14q11.2. A male infant, weighing 1,391 g, was delivered at term by cesarean section. Maternal and paternal karyotypes were 46,X,t(X; 14)(q28; q11) and 46,XY, respectively. These findings indicated that the sSMC might have originated from chromosome disjunction at a ratio of three to one. Here we describe a case with an sSMC derived from Xq28 and 14q11.2. Our findings suggest that this sSMC is most likely pathogenic. The collection of additional cases may be required.

Biallelic mutations of EGFR in a compound heterozygous state cause ectodermal dysplasia with severe skin defects and gastrointestinal dysfunction.

Epidermal growth factor receptor (EGFR), a receptor that recognizes epidermal growth factor, is a very important regulator of cell proliferation and differentiation. To date, three cases of severe ectodermal dysplasia were reported to be caused by an inherited germline homozygous loss-of-function missense mutation of EGFR. This is the first report of a patient with biallelic compound heterozygous mutations in EGFR.

Novel TFAP2A mutation in a Japanese family with Branchio-oculo-facial syndrome.

Branchio-oculo-facial syndrome (BOFS) is a rare autosomal dominant disorder characterized by craniofacial, ocular, and ectodermal anomalies. BOFS is caused by mutation of the transcription factor AP2-alpha gene (TFAP2A). We performed detailed genetic analysis of a Japanese family with clinically suspected BOFS and identified a novel missense mutation resulting in a predicted amino-acid substitution in the highly conserved basic DNA-binding domain of TFAP2A (NM_003220.2:c.699A>C).

The beneficial effects of long-term enzyme replacement therapy on cardiac involvement in Japanese Fabry patients.

Fabry disease is a hereditary disorder that occurs due to the reduction or absence of alpha-galactosidase A activity, which leads to cardiac involvement including left ventricular hypertrophy (LVH). Enzyme replacement therapy (ERT) provides better patient outcomes by preventing serious complications. However, there have been very few studies on the long-term effects of ERT on the cardiac manifestations in Japanese Fabry patients. We retrospectively analyzed the data from the medical records of 42 Fabry patients (male, n = 17; female, n = 25) who were followed at Jikei University Hospital, and in whom the long-term effects of ERT could be evaluated (median follow-up period: male, 11 years; female, 8 years). The slope of the left ventricular mass (LVM) increase was 3.02 ±â€¯3.41 g/m2/year in males and 1.69 ±â€¯2.73 g/m2/year in females. In a subgroup analysis, the slopes of males with and without LVH did not differ to a statistically significant extent; however, the slope in female patients without LVH was significantly smaller than that of female patients with LVH. We then compared our data to the natural historical data that have previously been reported. In comparison to the previously reported data, we found a significant reduction in the LVM changes (g/height2.7/year) of patients who received long-term ERT (male, 4.07 ±â€¯1.03 to 1.25 ±â€¯1.39; female, 2.31 ±â€¯0.81 to 0.78 ±â€¯1.23). Long-term ERT effectively prevents LVH in Fabry patients. This effect was also observed in the patients with LVH prior to the initiation of ERT.

Identification of Cryptic Novel α-Galactosidase A Gene Mutations: Abnormal mRNA Splicing and Large Deletions.

Anderson-Fabry (FD) disease is an inborn error of metabolism caused by a deficiency of α-galactosidase A (GLA), a lysosomal enzyme. Many male FD patients display a classic FD phenotype; however, some female patients have neither reduced leukocyte GLA enzyme activity level nor FD symptoms. Thus, GLA gene analysis is especially important for diagnosing suspected FD in female subjects. In this study, we revealed 4 novel GLA gene mutations in 5 independent families using GLA cDNA analysis and multiplex ligation-dependent probe amplification (MLPA) analysis. These distinct mutations included a large deletion mutation from intron 1 to exon 5 (c.195-471_c.691del5.5k, corresponding to g.8508_g.14069del5.5k), an insertion mutation of splicing enhancer sequence in intron 4 (c.639+329_c.639+330ins113, corresponding to g.12627_g.12628ins113), an insertion mutation of retrotransposon L1 in exon 4 (c.634_c.635, corresponding to g.12293_g.12294), and a non-SNP deep intronic point mutation in intron 3 (c.547+395G>C, corresponding to g.11727G>C). It is difficult to detect these mutations with direct sequencing of only the exonic element. When exonic mutations are not found in the GLA gene from suspected FD patients, GLA cDNA and MLPA analyses should be performed to detect large deletion/insertion and intronic mutations including transcription abnormalities.

Characteristics of Cerebral Microbleeds in Patients with Fabry Disease.

BACKGROUND AND PURPOSE: Fabry disease (FD) is an X-linked lysosomal storage disorder frequently associated with the central nervous system manifestations. Although white matter hyperintensity (WMH) on MRI has been previously reported, little is known about cerebral microbleeds (CMBs) in patients with FD. Our aim is to investigate the clinical characteristics of CMBs in patients with FD. METHODS: All patients with FD were diagnosed by enzyme activity and/or gene analysis at Jikei University Hospital. We retrospectively enrolled consecutive patients with FD who underwent MRI study, including fluid-attenuated inversion recovery and susceptibility-weighted imaging, between July 2008 and September 2013. After categorizing the patients into CMB-positive and CMB-negative groups, we compared the clinical characteristics between the 2 groups. RESULTS: We enrolled 54 patients (males, 24; median age 39 years, interquartile range; 29-50 years). The CMB-positive group included 16 (30%) patients. The number of males was significantly higher in the CMB-positive group than in the CMB-negative group (75% versus 32%, P = .003). The prevalence rates of chronic kidney disease (CKD) (estimated glomerular filtration rate < 60 mL/min/1.73 m(2)) and WMH were higher in the CMB-positive group than in the CMB-negative group (CKD: 44% versus 13%, P = .013; WMH: 88% versus 58%, P = .035). No significant differences in the number of vascular risk factors were observed between the 2 groups. CONCLUSIONS: The distinct characteristics of FD patients with CMBs were male sex, presence of CKD, and WMH. These factors may play an important role in the mechanism of hemorrhagic stroke in FD.

Prevalence of Fabry disease in dialysis patients: Japan Fabry disease screening study (J-FAST).

BACKGROUND: In Fabry disease, progressive glycolipid accumulation leads to damage in kidney and other organs. This study was designed to determine the prevalence rate of Fabry disease in Japanese dialysis patients. METHODS: All dialysis patients agreeing to Japan Fabry disease screening study (J-FAST) with informed consent were selected except for Fabry disease. The screening was performed by a method of measuring plasma and/or leukocytes lysosomal α-galactosidase A protein level and α-galactosidase A activity. If positive, genetic analysis was carried out upon patient's agreement. RESULTS: J-FAST dealt with 8547 patients (male 5408, female 3139). At the tertiary examination, 26 out of 8547 patients were found to be positive. Six out of 26 patients could not accept genetic analysis because of death. Remaining 20 patients agreed with genetic analysis; then 2 patients (male 2, female 0) had a variation of the α-Gal gene and 11 patients showed E66Q variations. Therefore, the frequency of Fabry disease in J-FAST was 0.04 % (2/5408) in males and 0 % (0/3139) in females, and then 0.02 % (2/8547) in all patients. The presumptive clinical diagnoses of end-stage kidney disease (ESKD) were 10 chronic glomerulonephritis, 7 diabetic nephropathy, 3 unknown etiology, 3 nephrosclerosis, 1 gouty nephropathy, 1 autosomal dominant polycystic kidney disease and 1 renal tuberculosis among 26 tertiary positive patients. Two male Fabry patients were initially diagnosed as nephrosclerosis and chronic glomerulonephritis. CONCLUSIONS: The prevalence rate of Fabry disease in J-FAST was 0.02 %. Moreover, Fabry disease could not be ruled out as the clinical diagnosis of ESKD.

Rapid Immunochromatographic Detection of Serum Anti-α-Galactosidase A Antibodies in Fabry Patients after Enzyme Replacement Therapy.

We developed an immunochromatography-based assay for detecting antibodies against recombinant α-galactosidase A proteins in serum. The evaluation of 29 serum samples from Fabry patients, who had received enzyme replacement therapy with agalsidase alpha and/or agalsidase beta, was performed by means of this assay method, and the results clearly revealed that the patients exhibited the same level of antibodies against both agalsidase alpha and agalsidase beta, regardless of the species of recombinant α-galactosidase A used for enzyme replacement therapy. A conventional enzyme-linked immunosorbent assay supported the results. Considering these, enzyme replacement therapy with agalsidase alpha or agalsidase beta would generate antibodies against the common epitopes in both agalsidase alpha and agalsidase beta. Most of the patients who showed immunopositive reaction exhibited classic Fabry phenotype and harbored gene mutations affecting biosynthesis of α-galactosidase A. As immunochromatography is a handy and simple assay system which can be available at bedside, this assay method would be extremely useful for quick evaluation or first screening of serum antibodies against agalsidase alpha or agalsidase beta in Fabry disease with enzyme replacement therapy.

Frequency of de novo mutations in Japanese patients with Fabry disease.

We examined alpha-galactosidase A (GLA) gene mutations in 74 Japanese families with Fabry disease (FD) to determine the frequency of de novo mutations. In 5 of 74 families (6.8%), the probands had no positive family histories and were diagnosed as de novo because their parents had no mutations in GLA gene. The parents of Fabry patients do not necessarily have mutations in GLA gene which is an important consideration in genetic counseling for FD.